This invention relates to an anchoring system, and more particularly to an anchoring system for use with portable arresting gear. The invention finds particular application in portable aircraft arresting systems and will be described with reference thereto; it should be appreciated however that the invention will also find application in many systems which must be anchored to the ground during use.
Aircraft arresting systems generally include an arresting cable or net which is positioned in normal orientation to a runway and deployed so as to engage a catching device on an aircraft, or the aircraft itself, when it lands on the runway. The cable and net are connected at their opposite ends to tapes which are mounted on reels at the side of the runway. The tape and/or reels have energy absorbing and braking apparatus connected thereto. In operation, the arresting cable or net is engaged by the landing aircraft and is dragged down the runway, pulling the tape from the reels as it goes.
Portable aircraft arresting systems have been provided heretofore comprising pullable wheeled trailers carrying energy absorbers or brake units and the other equipment necessary to provide a self-contained unit for aircraft arrestment. Such portable equipment is disclosed in co-pending U.S. patent application Ser. Nos. 581,807, filed Feb. 21, 1984 and 673,607, filed Nov. 21, 1984, which are assigned to the same assignee as the present application. In connection with the use of such portable systems, two of the towable trailers are positioned on opposite sides of an airstrip with the tape ends of the units aligned transversely of the runway with a cable or net attached to the tape ends and extending across the runway. Each trailer is ground supported and in operation the trailer wheels are elevated out of contact with the ground, and the trailer appropriately secured or anchored to concrete foundations or to the ground.
The anchoring of a portable arresting system to concrete foundations is only possible when the system can be deployed on an airstrip at a position which has been previously selected and prepared with the appropriate mounting foundations. Unfortunately, under many emergency circumstances, and particularly under wartime conditions, it is not possible to know in advance where on an airstrip it will be necessary to deploy an aircraft arresting system. Under such circumstances it is imperative that there be available a ground anchoring system which can be quickly installed on whatever type of runway or ground surface might exist at the runway position best situated for making aircraft arrestments.
Heretofore ground anchoring has been achieved by means of a plurality of anchor stakes driven into the ground through mounting holes in the frame of the towable trailers and with one or more offset anchoring systems. While several of the offset anchoring systems which have been heretofore available have been generally satisfactory for this application, they have had limitations attendant to their structure which have made their proper installation relatively laborious and difficult. The present invention is directed to an improved offset anchoring system which avoids the disadvantages of the systems previously known and which offers significant advantages over such systems with respect to ease of installation and certainty of proper operation.
Typical of the offset anchoring systems used heretofore is the Befab system which is comprised of frame mounted turnbuckle rod assemblies which are connected at their opposite ends to links which are in turn connected to one or more ground anchor rods. With this system, stakes are driven into the ground at the position of the end of the anchor rods and a rod connector bolted to the top of the stakes. The ends of the ground anchor rods are threaded so that they can be bolted to the stakes at the rod connectors. Once the anchor rods are bolted to the connectors, the entire assembly is tensioned by tightening the turnbuckle and the bolts on the end of the anchor rods. It is of great importance that the ground anchor rods be equally tensioned at the point loading of a stake/rod mounting set defeats the purpose of using multiple stakes and can lead to the successive failure of all the stakes of a ground anchor. To ensure maximum holding power, great care has also been taken heretofore to drive the stakes into the ground at a defined angle of attack. This has generally required two installers as the stakes must be held while they are started into the ground at the proper angle.